In the oilfield industry, many wells use a downhole reciprocating type production pump to lift oil from a borehole to the surface. Rods extend from the surface to the extraction area to enable a pump jack located at the surface to cause reciprocal movement of the rod and bring oil to the surface. These rods are known as sucker rods or pump rods and are typically between 25 and 40 feet in length, and threaded at both ends. Sometimes the sucker rods are made of fiberglass with metal end fittings and are typically 37.5 feet in length.
For various reasons, such as wear and tear, the sucker rods must be removed and replaced from time to time. Typically, upon removal, the metal sucker rod is subjected to various forms of inspection, reconditioning and or remanufacturing. In this manner, a used metal sucker rod can be safely returned to service.
Typically the main process of reclaiming or reconditioning a used metal rod utilized in oil pump wells comprises obtaining the rod, cleaning the rod to remove contaminates from use in oil extraction, performing a visual inspection of the rod body, the end fitting, gauging of the end fitting, and gauging the end threads after thread coupling has been removed to determine if the rod should be reconditioned.
However, in addition to metal sucker rods which can be reconditioned or reclaimed, fiberglass reinforced plastic sucker rods exist. The manufacturing of these sucker rods is taught in various patents such as U.S. Pat. No. 7,730,938. More particularly, fiberglass reinforced plastic sucker rods typically require the use of pultrusion machines. Subsequently, the fiberglass rods are attached to metal rod ends through the use of abrading materials and adhesives to attach the metal end to the fiberglass rod.
During assembly, in certain methods, adhesive is inserted into to an end fitting, which in turn is attached to the fiberglass rod end. After attachment, the area of interaction is heated to cure the adhesive. In this method, upon subsequent cooling, the rods are then pulled in a longitudinal manner to set the bond between the cured adhesive and the end fitting. By pulling during the assembly of the sucker rod, the rod can be inspected to check the integrity of the bond between the rod and the end fitting.
While metallic sucker rods have often been reclaimed, a procedure or method beyond cleaning and visually inspecting the used composite sucker rod has not been developed for the reclamation of used composite sucker rods such as fiberglass sucker rods, despite the fact that fiberglass sucker rods are lighter in weight than their metal counterparts and provide less stress on machinery which lowers or raises the sucker rods within a borehole. There would be great utility in developing methods for inspection and reclamation of composite sucker rods such that they can be reliably used again instead of requiring new composite sucker rods in downhole operations or used composite sucker rods of unproved reliability.